Merge pull request #122296 from tnqn/nftables-kernel-requirement

kube-proxy: change implementation of LoadBalancerSourceRanges for wider kernel support

pkg/proxy/nftables/helpers_test.go

@@ -210,6 +210,17 @@ func (tracer *nftablesTracer) addressMatches(ipStr, not, ruleAddress string) boo
 	}
 }
 
+func (tracer *nftablesTracer) noneAddressesMatch(ipStr, ruleAddress string) bool {
+	ruleAddress = strings.ReplaceAll(ruleAddress, " ", "")
+	addresses := strings.Split(ruleAddress, ",")
+	for _, address := range addresses {
+		if tracer.addressMatches(ipStr, "", address) {
+			return false
+		}
+	}
+	return true
+}
+
 // matchDestIPOnly checks an "ip daddr" against a set/map, and returns the matching
 // Element, if found.
 func (tracer *nftablesTracer) matchDestIPOnly(elements []*knftables.Element, destIP string) *knftables.Element {
@@ -267,6 +278,7 @@ func (tracer *nftablesTracer) matchDestPort(elements []*knftables.Element, proto
 // match verdictRegexp.
 
 var destAddrRegexp = regexp.MustCompile(`^ip6* daddr (!= )?(\S+)`)
+var destAddrLookupRegexp = regexp.MustCompile(`^ip6* daddr != \{([^}]*)\}`)
 var destAddrLocalRegexp = regexp.MustCompile(`^fib daddr type local`)
 var destPortRegexp = regexp.MustCompile(`^(tcp|udp|sctp) dport (\d+)`)
 var destIPOnlyLookupRegexp = regexp.MustCompile(`^ip6* daddr @(\S+)`)
@@ -278,6 +290,7 @@ var destDispatchRegexp = regexp.MustCompile(`^ip6* daddr \. meta l4proto \. th d
 var destPortDispatchRegexp = regexp.MustCompile(`^meta l4proto \. th dport vmap @(\S+)$`)
 
 var sourceAddrRegexp = regexp.MustCompile(`^ip6* saddr (!= )?(\S+)`)
+var sourceAddrLookupRegexp = regexp.MustCompile(`^ip6* saddr != \{([^}]*)\}`)
 var sourceAddrLocalRegexp = regexp.MustCompile(`^fib saddr type local`)
 
 var endpointVMAPRegexp = regexp.MustCompile(`^numgen random mod \d+ vmap \{(.*)\}$`)
@@ -400,6 +413,16 @@ func (tracer *nftablesTracer) runChain(chname, sourceIP, protocol, destIP, destP
 					rule = element.Value[0]
 				}
 
+			case destAddrLookupRegexp.MatchString(rule):
+				// `^ip6* daddr != \{([^}]*)\}`
+				// Tests whether destIP doesn't match an anonymous set.
+				match := destAddrLookupRegexp.FindStringSubmatch(rule)
+				rule = strings.TrimPrefix(rule, match[0])
+				if !tracer.noneAddressesMatch(destIP, match[1]) {
+					rule = ""
+					break
+				}
+
 			case destAddrRegexp.MatchString(rule):
 				// `^ip6* daddr (!= )?(\S+)`
 				// Tests whether destIP does/doesn't match a literal.
@@ -432,6 +455,16 @@ func (tracer *nftablesTracer) runChain(chname, sourceIP, protocol, destIP, destP
 					break
 				}
 
+			case sourceAddrLookupRegexp.MatchString(rule):
+				// `^ip6* saddr != \{([^}]*)\}`
+				// Tests whether sourceIP doesn't match an anonymous set.
+				match := sourceAddrLookupRegexp.FindStringSubmatch(rule)
+				rule = strings.TrimPrefix(rule, match[0])
+				if !tracer.noneAddressesMatch(sourceIP, match[1]) {
+					rule = ""
+					break
+				}
+
 			case sourceAddrRegexp.MatchString(rule):
 				// `^ip6* saddr (!= )?(\S+)`
 				// Tests whether sourceIP does/doesn't match a literal.

pkg/proxy/nftables/proxier.go

@@ -79,10 +79,8 @@ const (
 	kubeRejectChain            = "reject-chain"
 
 	// LoadBalancerSourceRanges handling
-	kubeFirewallSet             = "firewall"
+	kubeFirewallIPsMap     = "firewall-ips"
-	kubeFirewallCheckChain      = "firewall-check"
+	kubeFirewallCheckChain = "firewall-check"
-	kubeFirewallAllowSet        = "firewall-allow"
-	kubeFirewallAllowCheckChain = "firewall-allow-check"
 
 	// masquerading
 	kubeMarkMasqChain     = "mark-for-masquerade"
@@ -102,6 +100,7 @@ type servicePortInfo struct {
 	clusterPolicyChainName string
 	localPolicyChainName   string
 	externalChainName      string
+	firewallChainName      string
 }
 
 // returns a new proxy.ServicePort which abstracts a serviceInfo
@@ -117,6 +116,7 @@ func newServiceInfo(port *v1.ServicePort, service *v1.Service, bsvcPortInfo *pro
 	svcPort.clusterPolicyChainName = servicePortPolicyClusterChainNamePrefix + chainNameBase
 	svcPort.localPolicyChainName = servicePortPolicyLocalChainNamePrefix + chainNameBase
 	svcPort.externalChainName = serviceExternalChainNamePrefix + chainNameBase
+	svcPort.firewallChainName = servicePortFirewallChainNamePrefix + chainNameBase
 
 	return svcPort
 }
@@ -546,38 +546,20 @@ func (proxier *Proxier) setupNFTables(tx *knftables.Transaction) {
 	}
 
 	// Set up LoadBalancerSourceRanges firewalling
-	tx.Add(&knftables.Set{
+	tx.Add(&knftables.Map{
-		Name:    kubeFirewallSet,
+		Name:    kubeFirewallIPsMap,
-		Type:    ipvX_addr + " . inet_proto . inet_service",
+		Type:    ipvX_addr + " . inet_proto . inet_service : verdict",
 		Comment: ptr.To("destinations that are subject to LoadBalancerSourceRanges"),
 	})
-	tx.Add(&knftables.Set{
-		Name:    kubeFirewallAllowSet,
-		Type:    ipvX_addr + " . inet_proto . inet_service . " + ipvX_addr,
-		Flags:   []knftables.SetFlag{knftables.IntervalFlag},
-		Comment: ptr.To("destinations+sources that are allowed by LoadBalancerSourceRanges"),
-	})
 
 	ensureChain(kubeFirewallCheckChain, tx, createdChains)
-	ensureChain(kubeFirewallAllowCheckChain, tx, createdChains)
 	tx.Add(&knftables.Rule{
 		Chain: kubeFirewallCheckChain,
 		Rule: knftables.Concat(
-			ipX, "daddr", ".", "meta l4proto", ".", "th dport", "@", kubeFirewallSet,
+			ipX, "daddr", ".", "meta l4proto", ".", "th dport",
-			"jump", kubeFirewallAllowCheckChain,
+			"vmap", "@", kubeFirewallIPsMap,
 		),
 	})
-	tx.Add(&knftables.Rule{
-		Chain: kubeFirewallAllowCheckChain,
-		Rule: knftables.Concat(
-			ipX, "daddr", ".", "meta l4proto", ".", "th dport", ".", ipX, "saddr", "@", kubeFirewallAllowSet,
-			"return",
-		),
-	})
-	tx.Add(&knftables.Rule{
-		Chain: kubeFirewallAllowCheckChain,
-		Rule:  "drop",
-	})
 
 	// Set up service dispatch
 	tx.Add(&knftables.Map{
@@ -827,6 +809,7 @@ const (
 	serviceExternalChainNamePrefix          = "external-"
 	servicePortEndpointChainNamePrefix      = "endpoint-"
 	servicePortEndpointAffinityNamePrefix   = "affinity-"
+	servicePortFirewallChainNamePrefix      = "firewall-"
 )
 
 // hashAndTruncate prefixes name with a hash of itself and then truncates to
@@ -1001,11 +984,8 @@ func (proxier *Proxier) syncProxyRules() {
 	}
 
 	// We currently fully-rebuild our sets and maps on each resync
-	tx.Flush(&knftables.Set{
+	tx.Flush(&knftables.Map{
-		Name: kubeFirewallSet,
+		Name: kubeFirewallIPsMap,
-	})
-	tx.Flush(&knftables.Set{
-		Name: kubeFirewallAllowSet,
 	})
 	tx.Flush(&knftables.Map{
 		Name: kubeNoEndpointServicesMap,
@@ -1208,6 +1188,44 @@ func (proxier *Proxier) syncProxyRules() {
 			}
 		}
 
+		usesFWChain := len(svcInfo.LoadBalancerVIPStrings()) > 0 && len(svcInfo.LoadBalancerSourceRanges()) > 0
+		fwChain := svcInfo.firewallChainName
+		if usesFWChain {
+			ensureChain(fwChain, tx, activeChains)
+			var sources []string
+			allowFromNode := false
+			for _, src := range svcInfo.LoadBalancerSourceRanges() {
+				_, cidr, _ := netutils.ParseCIDRSloppy(src)
+				if cidr == nil {
+					continue
+				}
+				if len(sources) > 0 {
+					sources = append(sources, ",")
+				}
+				sources = append(sources, src)
+				if cidr.Contains(proxier.nodeIP) {
+					allowFromNode = true
+				}
+			}
+			// For VIP-like LBs, the VIP is often added as a local
+			// address (via an IP route rule).  In that case, a request
+			// from a node to the VIP will not hit the loadbalancer but
+			// will loop back with the source IP set to the VIP.  We
+			// need the following rules to allow requests from this node.
+			if allowFromNode {
+				for _, lbip := range svcInfo.LoadBalancerVIPStrings() {
+					sources = append(sources, ",", lbip)
+				}
+			}
+			tx.Add(&knftables.Rule{
+				Chain: fwChain,
+				Rule: knftables.Concat(
+					ipX, "saddr", "!=", "{", sources, "}",
+					"drop",
+				),
+			})
+		}
+
 		// Capture load-balancer ingress.
 		for _, lbip := range svcInfo.LoadBalancerVIPStrings() {
 			if hasEndpoints {
@@ -1224,53 +1242,19 @@ func (proxier *Proxier) syncProxyRules() {
 				})
 			}
 
-			if len(svcInfo.LoadBalancerSourceRanges()) > 0 {
+			if usesFWChain {
 				tx.Add(&knftables.Element{
-					Set: kubeFirewallSet,
+					Map: kubeFirewallIPsMap,
 					Key: []string{
 						lbip,
 						protocol,
 						strconv.Itoa(svcInfo.Port()),
 					},
+					Value: []string{
+						fmt.Sprintf("goto %s", fwChain),
+					},
 					Comment: &svcPortNameString,
 				})
-
-				allowFromNode := false
-				for _, src := range svcInfo.LoadBalancerSourceRanges() {
-					_, cidr, _ := netutils.ParseCIDRSloppy(src)
-					if cidr == nil {
-						continue
-					}
-					tx.Add(&knftables.Element{
-						Set: kubeFirewallAllowSet,
-						Key: []string{
-							lbip,
-							protocol,
-							strconv.Itoa(svcInfo.Port()),
-							src,
-						},
-						Comment: &svcPortNameString,
-					})
-					if cidr.Contains(proxier.nodeIP) {
-						allowFromNode = true
-					}
-				}
-				// For VIP-like LBs, the VIP is often added as a local
-				// address (via an IP route rule).  In that case, a request
-				// from a node to the VIP will not hit the loadbalancer but
-				// will loop back with the source IP set to the VIP.  We
-				// need the following rules to allow requests from this node.
-				if allowFromNode {
-					tx.Add(&knftables.Element{
-						Set: kubeFirewallAllowSet,
-						Key: []string{
-							lbip,
-							protocol,
-							strconv.Itoa(svcInfo.Port()),
-							lbip,
-						},
-					})
-				}
 			}
 		}
 		if !hasExternalEndpoints {

pkg/proxy/nftables/proxier_test.go

@@ -524,13 +524,9 @@ func TestOverallNFTablesRules(t *testing.T) {
 		add chain ip kube-proxy nat-prerouting { type nat hook prerouting priority -100 ; }
 		add rule ip kube-proxy nat-prerouting jump services
 
-		add set ip kube-proxy firewall { type ipv4_addr . inet_proto . inet_service ; comment "destinations that are subject to LoadBalancerSourceRanges" ; }
+		add map ip kube-proxy firewall-ips { type ipv4_addr . inet_proto . inet_service : verdict ; comment "destinations that are subject to LoadBalancerSourceRanges" ; }
-		add set ip kube-proxy firewall-allow { type ipv4_addr . inet_proto . inet_service . ipv4_addr ; flags interval ; comment "destinations+sources that are allowed by LoadBalancerSourceRanges" ; }
 		add chain ip kube-proxy firewall-check
-		add chain ip kube-proxy firewall-allow-check
+		add rule ip kube-proxy firewall-check ip daddr . meta l4proto . th dport vmap @firewall-ips
-		add rule ip kube-proxy firewall-allow-check ip daddr . meta l4proto . th dport . ip saddr @firewall-allow return
-		add rule ip kube-proxy firewall-allow-check drop
-		add rule ip kube-proxy firewall-check ip daddr . meta l4proto . th dport @firewall jump firewall-allow-check
 
 		add chain ip kube-proxy reject-chain { comment "helper for @no-endpoint-services / @no-endpoint-nodeports" ; }
 		add rule ip kube-proxy reject-chain reject
@@ -625,11 +621,13 @@ func TestOverallNFTablesRules(t *testing.T) {
 		add rule ip kube-proxy endpoint-GTK6MW7G-ns5/svc5/tcp/p80__10.180.0.3/80 update @affinity-GTK6MW7G-ns5/svc5/tcp/p80__10.180.0.3/80 { ip saddr }
 		add rule ip kube-proxy endpoint-GTK6MW7G-ns5/svc5/tcp/p80__10.180.0.3/80 meta l4proto tcp dnat to 10.180.0.3:80
 
+		add chain ip kube-proxy firewall-HVFWP5L3-ns5/svc5/tcp/p80
+		add rule ip kube-proxy firewall-HVFWP5L3-ns5/svc5/tcp/p80 ip saddr != { 203.0.113.0/25 } drop
+
 		add element ip kube-proxy service-ips { 172.30.0.45 . tcp . 80 : goto service-HVFWP5L3-ns5/svc5/tcp/p80 }
 		add element ip kube-proxy service-ips { 5.6.7.8 . tcp . 80 : goto external-HVFWP5L3-ns5/svc5/tcp/p80 }
 		add element ip kube-proxy service-nodeports { tcp . 3002 : goto external-HVFWP5L3-ns5/svc5/tcp/p80 }
-		add element ip kube-proxy firewall { 5.6.7.8 . tcp . 80 comment "ns5/svc5:p80" }
+		add element ip kube-proxy firewall-ips { 5.6.7.8 . tcp . 80 comment "ns5/svc5:p80" : goto firewall-HVFWP5L3-ns5/svc5/tcp/p80 }
-		add element ip kube-proxy firewall-allow { 5.6.7.8 . tcp . 80 . 203.0.113.0/25 comment "ns5/svc5:p80" }
 
 		# svc6
 		add element ip kube-proxy no-endpoint-services { 172.30.0.46 . tcp . 80 comment "ns6/svc6:p80" : goto reject-chain }
@@ -4267,7 +4265,6 @@ func TestSyncProxyRulesRepeated(t *testing.T) {
 		add chain ip kube-proxy filter-forward { type filter hook forward priority -101 ; }
 		add chain ip kube-proxy filter-input { type filter hook input priority -101 ; }
 		add chain ip kube-proxy filter-output { type filter hook output priority -101 ; }
-		add chain ip kube-proxy firewall-allow-check
 		add chain ip kube-proxy firewall-check
 		add chain ip kube-proxy forward
 		add chain ip kube-proxy mark-for-masquerade
@@ -4287,9 +4284,7 @@ func TestSyncProxyRulesRepeated(t *testing.T) {
 		add rule ip kube-proxy filter-input ct state new jump firewall-check
 		add rule ip kube-proxy filter-output ct state new jump endpoints-check
 		add rule ip kube-proxy filter-output ct state new jump firewall-check
-		add rule ip kube-proxy firewall-allow-check ip daddr . meta l4proto . th dport . ip saddr @firewall-allow return
+		add rule ip kube-proxy firewall-check ip daddr . meta l4proto . th dport vmap @firewall-ips
-		add rule ip kube-proxy firewall-allow-check drop
-		add rule ip kube-proxy firewall-check ip daddr . meta l4proto . th dport @firewall jump firewall-allow-check
 		add rule ip kube-proxy forward ct state invalid drop
 		add rule ip kube-proxy mark-for-masquerade mark set mark or 0x4000
 		add rule ip kube-proxy masquerading mark and 0x4000 == 0 return
@@ -4302,8 +4297,7 @@ func TestSyncProxyRulesRepeated(t *testing.T) {
 		add rule ip kube-proxy services ip daddr . meta l4proto . th dport vmap @service-ips
 		add rule ip kube-proxy services fib daddr type local ip daddr != 127.0.0.0/8 meta l4proto . th dport vmap @service-nodeports
 
-		add set ip kube-proxy firewall { type ipv4_addr . inet_proto . inet_service ; comment "destinations that are subject to LoadBalancerSourceRanges" ; }
+		add map ip kube-proxy firewall-ips { type ipv4_addr . inet_proto . inet_service : verdict ; comment "destinations that are subject to LoadBalancerSourceRanges" ; }
-		add set ip kube-proxy firewall-allow { type ipv4_addr . inet_proto . inet_service . ipv4_addr ; flags interval ; comment "destinations+sources that are allowed by LoadBalancerSourceRanges" ; }
 		add map ip kube-proxy no-endpoint-nodeports { type inet_proto . inet_service : verdict ; comment "vmap to drop or reject packets to service nodeports with no endpoints" ; }
 		add map ip kube-proxy no-endpoint-services { type ipv4_addr . inet_proto . inet_service : verdict ; comment "vmap to drop or reject packets to services with no endpoints" ; }
 		add map ip kube-proxy service-ips { type ipv4_addr . inet_proto . inet_service : verdict ; comment "ClusterIP, ExternalIP and LoadBalancer IP traffic" ; }